During World War II, the unit operated primarily in the Southwest Pacific Theater as part of Fifth Air Force.

During the course of World War II in the Pacific, the 8th participated in battles in Port Moresby, Nadaab, Owi, Zamboanga, the Philippines, Minadoro, Ie Shima and Japan.

The 8th Operations Group's origins go back to World War I, when the 33rd, 35th and 36th Aero Squadrons were activated in 1917 at Camp Kelly, Texas.

Significantly, on 11 October 1940, the 8th Pursuit Group participated in a test designed to compare the take-off runs of standard Navy and Army aircraft.

That experiment, the first time that Army planes had flown from a Navy carrier, foreshadowed the use of the ship in the ferry role that it performed admirably in World War II.

In December 1940, the group became part of the defense force for the New York metropolitan area, being reassigned to Mitchel Field on Long Island.

At Mitchel, the 33rd Pursuit Squadron was transferred to the 342d Composite Group in Iceland in August 1941 to engage in North Atlantic defense.

The group was assigned to the South West Pacific Theatre and deployed Brisbane, Australia, sailing on the Army Transport Ship Maui.

During the month of May the 35th and 36th were experiencing not only daily and night raids, but endured the shortage of food, excessive heat, rain, mud, mosquito's and necessary parts for planes and vehicles plus continuous alerts, bombing and strafing.

Returning to Townsville in June, the 35th and 36th Squadrons were equipped and prepared to leave for Oro Bay when word was received that the Japanese began offensive action to occupy the same territory.

The group went on to cover landings at Lingayen; support ground forces on Luzon; escort bombers to targets on the Asian mainland and on Formosa; and, in the last days of the war, attack enemy airfields and railways in Japan.

It began operations in the Korean War on 26 June 1950 by providing cover for the evacuation of US personnel from Seoul, entering into combat the next day.